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-   -   Not a Cub Onan, but a MF 1855 B48M (https://www.onlycubcadets.net/forum/showthread.php?t=56662)

EarlJ 03-28-2020 09:29 PM

Not a Cub Onan, but a MF 1855 B48M
 
Ok guys, hopefully someone here can help. I've asked in the onan forum on fb but no resolve. This engine is on my snapper/massey ferguson 1855. The engine is a b48m that I freshened up. New rings and gaskets, valve job, surfaced the heads. I'm linking the video on facebook so that you guys can hear what it's doing. Now since making the vid, I've reset the float, installed new intake gaskets, sprayed from here to doomsday for vac leaks none found.
Additionally, I swapped the plug wires around on the coil but no change. I checked the valves while running and they are moving freely and in spec. That weird part is the drivers side exhaust is way colder than the passenger side, in fact I can grab the drivers side no problem, the pass literally blistered my hand in an instance.

https://m.facebook.com/groups/831304...93702804052438

cooperino 03-29-2020 09:27 AM

Quote:

Originally Posted by EarlJ (Post 494164)
Ok guys, hopefully someone here can help. I've asked in the onan forum on fb but no resolve. This engine is on my snapper/massey ferguson 1855. The engine is a b48m that I freshened up. New rings and gaskets, valve job, surfaced the heads. I'm linking the video on facebook so that you guys can hear what it's doing. Now since making the vid, I've reset the float, installed new intake gaskets, sprayed from here to doomsday for vac leaks none found.
Additionally, I swapped the plug wires around on the coil but no change. I checked the valves while running and they are moving freely and in spec. That weird part is the drivers side exhaust is way colder than the passenger side, in fact I can grab the drivers side no problem, the pass literally blistered my hand in an instance.

https://m.facebook.com/groups/831304...93702804052438

How much compression on dead cylinder?

EarlJ 03-29-2020 07:58 PM

It's not dead per-se just cooler. Its firing, the cylinder is just cooler. I haven't done a compression check yet, can't locate my gauge...

cooperino 03-29-2020 08:21 PM

Quote:

Originally Posted by EarlJ (Post 494200)
It's not dead per-se just cooler. Its firing, the cylinder is just cooler. I haven't done a compression check yet, can't locate my gauge...

Ok.. a temp check then?? Maybe the Hot cylinder is the issue? Need more info. Blister VS cool is kinda vague.

green407 03-29-2020 08:33 PM

Quote:

Originally Posted by EarlJ (Post 494200)
It's not dead per-se just cooler. Its firing, the cylinder is just cooler. I haven't done a compression check yet, can't locate my gauge...

If you can hold onto it while the engine is running, it's dead. Maybe a bad plug, got one of the compression rings upside down, damaged head gasket, didn't stagger the rings? Could be anything.

ol'George 03-29-2020 08:33 PM

You should sizzle steak on the exhaust manifold on both sides.
Clearly the cool side is not producing power.
what color is the plug? fouled,wet? ????
something is not right on the cool side.

cooperino 03-30-2020 07:12 AM

Quote:

Originally Posted by EarlJ (Post 494200)
It's not dead per-se just cooler. Its firing, the cylinder is just cooler.

How do you know its firing? In your video "hard to tell" but it looked like it was missing pretty badly. From what I saw I would say it is not firing. These engine will run on one cylinder. Sometimes will even have enough power to move around pretty well. If you engage the blades at full throttle does it stall the engine? If so theres a real good chance the cylinder is dead as I suspected..

As a side note. George is 100% correct. Both sides should burn your hand on contact. I think you threw me off a little by saying cooler. The temp difference should really be no more than 20 degrees. When you said cooler I assumed it to be just slightly outside that parameter.

EarlJ 03-30-2020 04:47 PM

I've pulled the plug and checked for spark, it was beautiful. Now it seems to that the plug is fuel fowling, its wet. Installed a new plug ran a few mins did the same thing. Now I'm of the thought, I'm flooding and that being the long side of the manifold would be the reason it's fowling out. I think maybe I should order a brass float or swap this carb out.

cooperino 03-31-2020 08:02 AM

Quote:

Originally Posted by EarlJ (Post 494249)
I've pulled the plug and checked for spark, it was beautiful. Now it seems to that the plug is fuel fowling, its wet. Installed a new plug ran a few mins did the same thing. Now I'm of the thought, I'm flooding and that being the long side of the manifold would be the reason it's fowling out. I think maybe I should order a brass float or swap this carb out.

OK..Well, that I guess could happen, However, a wet plug can happen from other things. Typically if your flooding an engine like this it effects both cylinders. I would do a compression test before ordering parts.

EarlJ 04-01-2020 12:37 AM

I've done compression check wet cylinder has 90psi and the other has 85psi. I'm thinking to order one of the nikki carbs from ebay. Pretty sure my carb is just wore out.


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